Referring to FIG. 1 of the drawings, the reference numeral 100 generally designates a portion of a convention communications system. As shown, a base station system 102 operates to provide communications between a network interface 106 and an air interface, which is typically used for wireless communications. The base station system 102 generally comprises radio equipment 108 and a radio equipment controller 110, which each have a physical layer (PHY) 112 and 114 that communicate with each other over a CPRI/OBSAI link 113. Typically, though, the CPRI/OBSAI link 113 supports multiple data rates (for example 8), which can be supported by one (or more) of several reference clock frequencies. Setting the reference clock frequency to match the data rate over the CPRI/OBSAI link 113, however, has been difficult because such detection generally uses high speed circuitry, which is both power and area intensive. Therefore, there is a need for an improved timing circuit with an ARS function.
Some other examples of conventional circuits are: U.S. Pat. No. 6,158,014; U.S. Pat. No. 7,093,151; U.S. Pat. No. 7,295,554; U.S. Pat. No. 7,359,432; U.S. Pat. No. 7,593,498; U.S. Pre-Grant Publ. Patent No. 2008/0080600.